Hortonworks, whose Hadoop software has been a big driver of the current interest in Big Data, raised $100 million at a valuation of more than $1 billion as it prepares to go public sometime in 2015.

The funding round, which was co-led by investment giant BlackRock and hedge fund Passport Capital, is yet another demonstration of investors’ intense interest in pre-IPO companies and their belief that Big Data is going to produce some big returns.

Hortonworks competes directly with Cloudera, which raised $160 million in new funding earlier this month for its own flavor of Hadoop–an open source project developed at Yahoo. from a paper published by Google. that can store and process enormous amounts of data.

Both companies now have similar amounts of funding—about $225 million for Hortonworks and $300 million for Cloudera—and similar valuations, although neither would say how much more than $1 billion their valuations are.

Hortonworks Chief Executive Rob Bearden said he expects both companies to become public. Hortonworks expects to finish 2014 with about $100 million in revenue. The company has several members of the original Hadoop team from Yahoo.

“Our job is to make Apache Hadoop a truly enterprise-viable data platform, and…without those people, you can’t pull this off,” he said.

Choosing public market investors for a pre-IPO round—a strategy that Cloudera also pursued since its round was led by T. Rowe Price—is part of becoming a big public company, Bearden said.

“[BlackRock and Passport] help us think through so accurately what and how to drive our strategy forward as a public market company…They are also extraordinarily focused on where IT infrastructure is evolving and how that evolution will unpack,” he said.

Even though Hortonworks and Cloudera both offer Hadoop, they’re taking it in somewhat different directions. Hortonworks has focused on strengthening the open source core of Hadoop so that it can, for instance, become more interactive rather than just processing data in batches, and become more responsive in real time, Bearden said.

Cloudera in October released an Enterprise Data Hub to help companies manage data on top of Hadoop, a product that takes it into more direct competition with big technology vendors such as EMC Corp. and International Business Machines Corp.

“Hadoop is a collection of open source projects, and we make it become enterprise-grade,” Cloudera Chief Executive Tom Reilly told Venture Capital Dispatch last week.

Both chief executives say their companies have big ambitions. Reilly told CIO Journal that he’s building “a $20 billion company,” while Bearden said that in three or four years, Hortonworks could be managing “half the world’s data. So we have to execute flawlessly on our strategy, and I think we’re on track for that.”

Other Hadoop vendors include MapR Technologies, which is venture-backed, and Pivotal, which is a joint venture between EMC and VMware Inc. that’s backed by General Electric, which bought a 10% stake last year.